JP2015171178A - Power conditioner, and photovoltaic power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adopt a smoothing capacitor that is small-sized and has a long life, for a power conditioner or the like that is connected to a photovoltaic panel and adjusts power output from the photovoltaic panel.SOLUTION: A power conditioner comprises: a plurality of chopper circuits 21 to 24 provided correspondingly to a plurality of photovoltaic panels 11 to 14, respectively; a smoothing capacitor 25 connected in common to the plurality of chopper circuits 21 to 24; an inverter circuit 26 provided at a stage posterior to the smoothing capacitor 25; and an interleave control circuit 27 for making a timing of power chopping be cyclically different across the plurality of chopper circuits 21 to 24.

Description

  The present invention relates to a power conditioner that is connected to a solar panel and adjusts the power output from the solar panel, and a photovoltaic power generation system that includes the power conditioner and the solar panel.

  Conventionally, a solar panel is installed on the roof or garden of a house, and a power conditioner is connected to the solar panel, and the power obtained from the solar panel is consumed for home use or surplus power is sold. Systems that do this are known. The power conditioner used for this application generally has a chopper circuit for chopping the electric power obtained by the solar panel and an inverter circuit provided in the subsequent stage. A smoothing capacitor is provided between the chopper circuit and the inverter circuit for suppressing ripples generated by the chopping operation in the chopper circuit.

  Here, a multi-string power conditioner that adjusts the power of a plurality of solar panels connected in series is known (see Patent Documents 1 to 4).

  In addition, interleave control is known as a control technique used for general power supply devices (see Patent Documents 5 to 7).

JP 2013-183578 A JP 2013-102631 A JP 2013-101500 A JP 2012-181575 A JP 2013-212011 A JP2013-143828A Japanese Patent Laid-Open No. 08-084465

  In a power conditioner, a large-capacity electrolytic capacitor such as 500 μF is conventionally used as a smoothing capacitor disposed between a chopper circuit and an inverter circuit. However, electrolytic capacitors are large in size and require a large installation volume. In addition, this electrolytic capacitor is a component having a considerably short lifetime among electronic components, and the lifetime of this electrolytic capacitor is the law for extending the lifetime of the power conditioner.

  An object of this invention is to provide the power conditioner and solar power generation system which can employ | adopt a small long-life smoothing capacitor in view of the said situation.

The power conditioner of the present invention that achieves the above object is as follows.
A plurality of chopper circuits that are provided corresponding to each of the plurality of solar panels and boost the power output from the corresponding solar panels;
A smoothing capacitor provided in a subsequent stage of the plurality of chopper circuits, and connected in common to the plurality of chopper circuits;
An inverter circuit provided in a subsequent stage of the smoothing capacitor;
An interleave control circuit that cyclically varies the timing of chopping the power output from each of the plurality of solar panels across a plurality of chopper circuits is provided.

  Here, in the power conditioner of the present invention, the smoothing capacitor is preferably a ceramic capacitor or a film capacitor.

  The power conditioner of the present invention includes a plurality of chopper circuits corresponding to a plurality of solar panels, and the timing of chopping is varied cyclically across the plurality of chopper circuits. For this reason, the inverter circuit connected in common to the plurality of chopper circuits is supplied with electric power in which the ripple component is suppressed by equalizing the ripple waveforms of the plurality of chopper circuits. Therefore, the smoothing capacitor provided between the chopper circuit and the inverter circuit may be a small-capacitance capacitor. As a result, a small and long-life capacitor such as a ceramic capacitor or a film capacitor can be employed as the smoothing capacitor.

  In the power conditioner of the present invention, it is preferable that the interleave control circuit is a circuit that can freely switch a chopping timing in accordance with the number of chopper circuits to be controlled.

  When a solar panel is installed on the roof or garden of a house, the number of installed panels varies depending on the shape of the roof, the area of the garden, and the like. It is necessary to change the timing of the interleave control in accordance with the number of installed sheets. That is, the timing of chopping needs to be sequentially shifted by 120 ° when the number of installed solar panels is three and by 90 ° when four. Therefore, if a chopping timing switching function is added to the interleave control circuit, the same interleave control circuit can be used even if the number of installed solar panels is different.

  In the power conditioner of the present invention, it is preferable that the interleave control circuit adjusts the timing of chopping so as to reduce the ripple of the input power to the inverter.

  Basically, as described above, the timing of chopping is shifted by 120 ° in the case of 3 solar panels installed, by 90 ° in the case of 4 solar panels. The amount of power generated by each solar panel changes from moment to moment depending on the position of the sun and the weather. For this reason, the ripple can be further reduced by adjusting the chopping timing according to the situation that changes every moment without fixing the chopping timing to 120 ° or 90 °, for example.

  Moreover, the photovoltaic power generation system of the present invention that achieves the above object is characterized by comprising a plurality of solar panels and the power conditioner of the present invention.

  Here, the photovoltaic power generation system of the present invention includes the power conditioner of any of the above aspects of the present invention.

  According to the above-described present invention, a small and long-life smoothing capacitor can be employed.

It is the block diagram which showed 1st Embodiment of the solar energy power generation system of this invention. It is the schematic diagram which showed the ripple of the output of a chopper circuit. It is the block diagram which showed 2nd Embodiment of the solar energy power generation system of this invention. It is the block diagram which showed 3rd Embodiment of the solar energy power generation system of this invention.

  Embodiments of the present invention will be described below.

  FIG. 1 is a block diagram showing a first embodiment of the photovoltaic power generation system of the present invention. The photovoltaic power generation system of the first embodiment includes the first embodiment of the power conditioner of the present invention. The same applies to each embodiment described later.

  Here, a solar panel group 1 and a power conditioner 2A are provided.

  The solar panel group 1 is composed of four solar panels 11 to 14 in this embodiment. These four solar panels 11 to 14 are installed on the roof of a general household or in a garden.

  The power conditioner 2 </ b> A includes chopper circuits 21 to 24, a smoothing capacitor 25, an inverter circuit 26, and an interleave control circuit 27 that are provided corresponding to the solar panels 11 to 14, respectively. It should be noted that each element constituting this embodiment, that is, the chopper circuits 21 to 24, the inverter circuit 26, or the interleave control circuit 27 is an already known technique, and detailed description of each individual circuit is omitted here. To do.

  The chopper circuits 21 to 24 are circuits for chopping and boosting each power output from the corresponding solar panels 11 to 14. Outputs from these chopper circuits 21 to 24 are input to a smoothing capacitor 25 provided in common to the chopper circuits 21 to 24 at a subsequent stage of the chopper circuits 21 to 24. As the smoothing capacitor 25, for example, a ceramic capacitor or a film capacitor having a small capacity of about 30 μF and a small size and having a much longer life than an electrolytic capacitor is employed.

  An inverter circuit 26 is provided after the smoothing capacitor 25. The output power from the inverter circuit 26 is used as household power, or the surplus power is sold to a power company.

  Further, an interleave control circuit 27 is provided here. This interleave control circuit 27 is a circuit that performs control to cyclically vary the chopping timing of the power output from each of all the solar panels 11 to 14 across all the chopper circuits 21 to 24 shown here. is there.

  The interleave control circuit 27 of the present embodiment is configured to set the number of solar panels constituting the solar panel group 1 (for example, four solar panels 11 to 14 shown here), and interleave control. In the circuit 27, the chopping timing is switched according to the set number of sheets. Specifically, since the four solar panels 11 to 14 are provided in the example shown here, the interleave control circuit 27 is set to the number “4”. Then, the interleave control circuit 27 controls the timing of chopping in these inverter circuits so that the chopping in the four inverter circuits 21 to 24 is sequentially performed at a timing shifted by 90 °.

  Similarly, when the number of solar panels constituting the solar panel group is three, for example, the number of sheets “3” is set in the interleave control circuit 27. Then, the interleave control circuit controls the three inverter circuits so that the chopping in the three inverter circuits corresponding to the three solar panels is sequentially performed at a timing shifted by 120 °. When the number of solar panels is “6”, the angle is 60 °. In this way, the interleave control circuit 27 controls the chopping timing so as to obtain a phase difference obtained by dividing 360 ° by the set number according to the set number.

  FIG. 2 is a schematic diagram showing ripples in the output of the chopper circuit.

  (1) to (4) in FIG. 2 (A) are diagrams showing the outputs of the four chopper circuits 11 to 14 when they are independent. The phases of the ripples are successively different by 90 °, but each has a large ripple.

  FIG. 2B is a diagram in which the ripples of the respective outputs shown in FIG.

  FIG. 2C is a diagram showing a state where the four ripples shown in FIG. 2B are added.

  Here, as a result of performing the interleave control, the ripple of the entire power input to the inverter circuit 26 is greatly reduced as shown in FIG. Therefore, the smoothing capacitor 25 may be a small, small-capacity capacitor (for example, about 30 μF), and a long-life capacitor such as a ceramic capacitor or a film capacitor can be used as the smoothing capacitor 25.

  FIG. 3 is a block diagram showing a second embodiment of the photovoltaic power generation system of the present invention.

  In the second embodiment shown in FIG. 3, the same elements as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals as those in FIG. To do.

  The solar power generation system according to the second embodiment shown in FIG. 3 includes a solar panel group 1 and a power conditioner 2B. The difference between the power conditioner 2 </ b> B of the second embodiment and the power conditioner 2 </ b> A of the first embodiment is in the interleave control circuit 28.

  The interleave control circuit 27 in the first embodiment described above controls the chopping timings in the chop circuits 21 to 24 in a fixed manner so as to achieve a phase difference corresponding to the set number of sheets.

  The interleave control circuit 28 in the second embodiment shown in FIG. 3 is also controlled until the chopping timing in the chopper circuits 21 to 24 becomes a phase difference corresponding to the set number of sheets. The same as the interleave control circuit 27 in FIG. The interleave control circuit 28 according to the second embodiment further monitors the outputs of the solar panels 11 to 14, and in the chopper circuits 21 to 24 according to the output that changes momentarily according to the position of the sun, the weather, and the like. It has a function to fine-tune the timing of chopping. In the case of the present embodiment, the ripple can be further reduced by this function as compared with the first embodiment described above.

  FIG. 4 is a block diagram showing a third embodiment of the photovoltaic power generation system of the present invention.

  In the third embodiment shown in FIG. 4, the same elements as those in the first and second embodiments shown in FIGS. 1 and 3 are the same as the reference numerals in FIGS. Only the differences will be described.

  The solar power generation system of the third embodiment shown in FIG. 4 includes a solar panel group 1 and a power conditioner 2C. The difference between the power conditioner 2 </ b> C of the third embodiment and the power conditioners 2 </ b> A and 2 </ b> B of the first embodiment and the second embodiment is in the interleave control circuit 29.

  As described above, the interleave control circuit 27 according to the first embodiment controls the chopping timings in the chop circuits 21 to 24 in a fixed manner so as to achieve a phase difference corresponding to the set number of sheets.

  The interleave control circuit 29 according to the third embodiment also performs control so that the chopping timing in the chopper circuits 21 to 24 becomes a phase difference corresponding to the set number of sheets. Is the same.

  The interleave control circuit 29 of the third embodiment further has a function of directly monitoring the ripple waveform of the input of the inverter circuit 26 and finely adjusting the chopping timing in each of the chopper circuits 21 to 24 according to the ripple waveform. ing. In the case of the present embodiment as well, the ripple can be further reduced by this function as in the second embodiment described above, compared to the first embodiment described above.

1 Solar Panel Group 2A, 2B, 2C Power Conditioner 11-14 Solar Panel 21-24 Chopper Circuit 25 Smoothing Capacitor 26 Inverter Circuit 27, 28, 29 Interleave Control Circuit

Claims (5)

A plurality of chopper circuits that are provided corresponding to each of the plurality of solar panels and boost the power output from the corresponding solar panels;
A smoothing capacitor provided downstream of the plurality of chopper circuits and connected in common to the plurality of chopper circuits;
An inverter circuit provided in a subsequent stage of the smoothing capacitor;
A power conditioner comprising: an interleave control circuit that cyclically varies the timing of chopping the power output from each of the plurality of solar panels across the plurality of chopper circuits.   2. The power conditioner according to claim 1, wherein the smoothing capacitor is a ceramic capacitor or a film capacitor.   3. The power conditioner according to claim 1, wherein the interleave control circuit is a circuit capable of switching a chopping timing in accordance with the number of the chopper circuits to be controlled.   The power conditioner according to any one of claims 1 to 3, wherein the interleaving control circuit adjusts the timing of the chopping so as to reduce a ripple of input power to the inverter. Multiple solar panels,
A photovoltaic power generation system comprising the power conditioner according to any one of claims 1 to 4.

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